July 2012 solar storm

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The solar storm of 2012 was an unusually large and strong coronal mass ejection (CME) event that occurred on July 23 that year. It missed Earth with a margin of approximately nine days, as the equator of the Sun rotates around its own axis with a period of about 25 days.[1]

Solar storm of 2012
CME of 23 July 2012.jpg
The coronal mass ejection, as photographed by STEREO
DateJuly 23, 2012 (2012-07-23)
TypeCoronal mass ejection
OutcomeMissed striking the Earth by nine days
Part of Solar cycle 24

The region that produced the outburst was thus not pointed directly towards Earth at that time. The strength of the eruption was comparable to the 1859 Carrington Event that caused damage to electrical equipment worldwide, which at that time consisted mostly of telegraph systems.[2]


The event occurred in 2012, near the local maximum of sunspots that can be seen in this graph.

The eruption tore through Earth's orbit, hitting the STEREO-A spacecraft. The spacecraft is a solar observatory equipped to measure such activity, and because it was far away from the Earth and thus not exposed to the strong electrical currents that can be induced when a CME hits the Earth's magnetosphere,[2] it survived the encounter and provided researchers with valuable data.

Based on the collected data, the eruption consisted of two separate ejections which were able to reach exceptionally high strength as the interplanetary medium around the Sun had been cleared by a smaller CME four days earlier.[2]

The event occurred at a time of high sunspot activity during solar cycle 24.

Predicted effectsEdit

Had the CME hit the Earth, it is likely that it would have inflicted serious damage to electronic systems on a global scale.[2] A 2013 study estimated that the economic cost to the United States would have been between US$600 billion and $2.6 trillion.[3] Ying D. Liu, professor at China's State Key Laboratory of Space Weather, estimated that the recovery time from such a disaster would have been about four to ten years.[4]

Historical comparisonsEdit

The record fastest CME associated with the August 1972 solar storm is thought to have occurred in a similar process of earlier CMEs clearing particles in the path to Earth. This storm arrived in 14.6 hours, an even shorter duration after the parent flare erupted than for the great solar storm of 1859.

See alsoEdit


  1. ^ Williams, D. R. (July 1, 2013). "Sun Fact Sheet". NASA. Retrieved January 13, 2015.
  2. ^ a b c d Phillips, Tony (July 23, 2014). "Near Miss: The Solar Superstorm of July 2012". Science@NASA. NASA. Retrieved January 10, 2015.
  3. ^ Solar Storm Risk to the North American Electric Grid Lloyd's 2013
  4. ^ Sanders, Robert (March 18, 2014). "Fierce solar magnetic storm barely missed Earth in 2012". UC Berkeley News Center. Retrieved January 10, 2015.

External linksEdit